Wondering how to measure a tree using a Clinometer? Wow? Did you actually say yes? That's kind of sad, but I got you covered.
Assuming that you know your own height and have an appropriate measuring tool preferably measuring tape, the process is actually quite simple.
One of the most quintessential steps to finding the missing side of an object using a clinometer is to ensure that you are standing at a designated distance. In this instance I'm standing away from the tree at a distance of 26 meters
Now, using your clinometer and a friend you should be able to find the angle of elevation which in this case is 35 degrees. The string attached will sort of hover over the nearest angle.
Now, the easy part. With the trusty aid of a calculator all you have to do is plug in the "Tan" formula with the measurements you got to get a length for the missing side. Which in my case would be 26 multiplied by tan 35.
The answer I got was rounded to decimal places and is 18.2. Now all I have to do is add my eight which is 1.8 metres and Boom. the missing side works out to be 20 metres.